#!/usr/bin/env vpython3

#  Copyright 2016 The WebRTC project authors. All Rights Reserved.
#
#  Use of this source code is governed by a BSD-style license
#  that can be found in the LICENSE file in the root of the source
#  tree. An additional intellectual property rights grant can be found
#  in the file PATENTS.  All contributing project authors may
#  be found in the AUTHORS file in the root of the source tree.
"""Script for merging generated iOS libraries."""

import sys
import argparse
import os
import re
import subprocess
from six.moves import range


# Valid arch subdir names.
VALID_ARCHS = ['arm_libs', 'arm64_libs', 'ia32_libs', 'x64_libs']


def MergeLibs(lib_base_dir):
  """Merges generated iOS libraries for different archs.

  Uses libtool to generate FAT archive files for each generated library.

  Args:
    lib_base_dir: directory whose subdirectories are named by architecture and
                  contain the built libraries for that architecture

  Returns:
    Exit code of libtool.
  """
  output_dir_name = 'fat_libs'
  archs = [arch for arch in os.listdir(lib_base_dir) if arch in VALID_ARCHS]
  # For each arch, find (library name, libary path) for arch. We will merge
  # all libraries with the same name.
  libs = {}
  for lib_dir in [os.path.join(lib_base_dir, arch) for arch in VALID_ARCHS]:
    if not os.path.exists(lib_dir):
      continue
    for dirpath, _, filenames in os.walk(lib_dir):
      for filename in filenames:
        if not filename.endswith('.a'):
          continue
        entry = libs.get(filename, [])
        entry.append(os.path.join(dirpath, filename))
        libs[filename] = entry
  orphaned_libs = {}
  valid_libs = {}
  for library, paths in list(libs.items()):
    if len(paths) < len(archs):
      orphaned_libs[library] = paths
    else:
      valid_libs[library] = paths
  for library, paths in list(orphaned_libs.items()):
    components = library[:-2].split('_')[:-1]
    found = False
    # Find directly matching parent libs by stripping suffix.
    while components and not found:
      parent_library = '_'.join(components) + '.a'
      if parent_library in valid_libs:
        valid_libs[parent_library].extend(paths)
        found = True
        break
      components = components[:-1]
    # Find next best match by finding parent libs with the same prefix.
    if not found:
      base_prefix = library[:-2].split('_')[0]
      for valid_lib, valid_paths in list(valid_libs.items()):
        if valid_lib[:len(base_prefix)] == base_prefix:
          valid_paths.extend(paths)
          found = True
          break
    assert found

  # Create output directory.
  output_dir_path = os.path.join(lib_base_dir, output_dir_name)
  if not os.path.exists(output_dir_path):
    os.mkdir(output_dir_path)

  # Use this so libtool merged binaries are always the same.
  env = os.environ.copy()
  env['ZERO_AR_DATE'] = '1'

  # Ignore certain errors.
  libtool_re = re.compile(r'^.*libtool:.*file: .* has no symbols$')

  # Merge libraries using libtool.
  libtool_returncode = 0
  for library, paths in list(valid_libs.items()):
    cmd_list = [
        'libtool', '-static', '-v', '-o',
        os.path.join(output_dir_path, library)
    ] + paths
    libtoolout = subprocess.Popen(cmd_list, stderr=subprocess.PIPE, env=env)
    _, err = libtoolout.communicate()
    for line in err.splitlines():
      if not libtool_re.match(line):
        print(line, file=sys.stderr)
    # Unconditionally touch the output .a file on the command line if present
    # and the command succeeded. A bit hacky.
    libtool_returncode = libtoolout.returncode
    if not libtool_returncode:
      for i in range(len(cmd_list) - 1):
        if cmd_list[i] == '-o' and cmd_list[i + 1].endswith('.a'):
          os.utime(cmd_list[i + 1], None)
          break
  return libtool_returncode


def main():
  parser_description = 'Merge WebRTC libraries.'
  parser = argparse.ArgumentParser(description=parser_description)
  parser.add_argument('lib_base_dir',
                      help='Directory with built libraries. ',
                      type=str)
  args = parser.parse_args()
  lib_base_dir = args.lib_base_dir
  MergeLibs(lib_base_dir)


if __name__ == '__main__':
  sys.exit(main())